I want to start a basic mage pvp thread for myself and whoever else wants to add. These are some things I picked up from research and my many losses in durotar:

Gearing for PVP

Here are some base stats to aim for: 100 spell penetration, 4-6% hit rating, ~400 haste, ~800 resilience.
100 spell pen = mitigates resistances (auras, totems, etc) , 4% hit rating is minimum needed to hit lvl 80 target (6% if you include racial bonuses), haste for larger shatters, resi for survivability.

After this, stacking haste is the most popular stat for frost mages. More haste = less global cooldown = faster instant casts, faster poly, more spells added into your shatter etc etc.

As for major glyphs, evocation is absolutely essential, if you get a full evo off it's like having another health bar. There is some leeway for the other two, I personally use icy veins and polymorph. For minor glyphs, the preferred ones are frost ward, fire ward, and slow fall.

General PVP

Learn to fake cast. You want your opponents to blow their spell interrupt cooldowns: CS, spell reflect, spell lock, kick etc. To fake cast, start and stop casting immediately so your spells doesn't get locked. A similar effect can be achieved by casting from a diff spell school. I.E. Cast scorches as a frost mage, if the opponent locks out your fire school, they have to eat 20 seconds of frostbolts.

Use icy veins + evocation together. Icy veins gives you a faster evocation and no spell pushback whatsoever. This can be a lifesaver.

Polymorph. Often times people will trinket your first poly, so begin casting a follow up poly just in case.

Fingers of Frost. FoF has a "ghost charge." Meaning, even with one charge left you can frostbolt and immediately ice lance and both will crit.

Duels

vs melee in general.
Learn to effectively use each freeze. Download shield monitor to know when your ice barrier is gonna break. Don't overlap shattered barrier and frost nova. A wasted nova means a wasted shatter, remember that.

vs warriors. Jump during the charge. Blink after an intercept. Pop all pets and cooldowns. He'll be stuck taking dmg. Even if he lolstorms pets he will take a lot of dmg from you while trying to kill them. After this initial burst, dead range the warrior (10y?) so he can't charge you. Also whenever he spell reflects just icelance to get rid of it.

vs rogues. Time your iceblock and trinket carefully, this is a cooldown war. Don't iceblock before cloak of shadows, AoE immediately once he vanishes, and generally I'd say don't blink unless he kidney shots you. Some rogues know this though and will never use kidney. If you do find yourself off blink CD and you need to trinket the kidney, follow up with water ele so he can't blind and get out of combat.

vs hunters. Get close to them. Make them melee you. We have a lot of roots between shattered barrier, frost nova, pet nova, etc. Use them and close the distance. If beast mastery, their pet will rape you, LoS the hunter and kill the pet first. If your low, evocate during his deterrence.

vs ret pallys. Spellsteal everything and keep your distance. Keep doing R1 frost bolt to stack debuffs so he can't dispel the slows. Of all the classes, we counter rets the hardest, should be an easy win.

vs shaman.
enh. Mage armor to reduce freeze times. Icelance the grounding totem. Blanket CS, so he can't windshear, then sheep. Re-cast sheep in case of immediate trinket. Spellsteal his buffs and begin nuke. If he calls wolves, invis out, then reset fight.
vs. ele. Icelance grounding totem. R1 Frostbolt to bait windshear on frost school. After he shears, sheep him. Peel buffs and get rid of totems. If he trinkets this sheep, he will eat a full deep freeze so you're at an advantage. Blow cooldowns and begin nuke. Keep your distance and watch for the instant lava burst, ice block it. The shaman's one spellschool is nature, so a counterspell can completely screw them. Use deep freeze not only for nuke but as a 2nd interrupt after CS wears off.

vs mage.
frost. This is essentially a mana war. Prebuff with frostward and slowfall. Spellsteal until you get his ice barrier, then begin instant casts. Don't bother spellstealing mana shield, just fireblast into it to waste his mana. I actually have "/cancelaura mana shield" macro'd to my spellsteal. Taking dmg to mana shield WILL make you lose.
arcane mage. This is a hard fight, don't buff icebarrier unless you need it. Juking his CS and getting a full CS on his arcane school is key. Also you have water ele which he does not.
vs all. Try to get a a full sheep in the beginning to bait trinket. If he trinkets, freeze him, he'll most likely blink. After that range nova, deep freeze. He'll most likely eat a full shatter giving you a good advantage.

vs locks.
destro. R1 frostbolt lock to cover dispels, sheep him, begin nuke on pet (kill it twice if necessary). Try to juke his spellock. If you have los, use it to avoid fears. CS the fire school. If you don't have LoS, know that fear has a short range. Kite the lock, while trying to kill the pet. TBH, lock vs mage in open space is one of the hardest fights.

vs DKs.
You'll have to kite both the pet and the DK. The pet does too much damage for you to just let it go. Save trinket for pet stun. Use mage armor to reduce chains of ice. Counter-spell the DK when you feel like you can land a kill, he won't be able to eat his pet (it also locks out deathcoils, AMS, etc). If he pulls gargoyle, on rtk try to kill it, on GD you need to LoS (25k gaygoyle is skill).

Finally :p. Been busy w exam so no time to browse forums.. But this is really what i am looking for :p. I will be speccing Raiding Fire Off-spec for a while with new content, but eventually (most likely) will spec Frost PvP .

*reading again* *takes down notes*

Thanks Melk :3.. nothing to add of course, partly cos i dont know much